Papillomavirus virions. Coloured transmission electron micrograph (TEM) of papillomavirus virions (purple). Papillomaviruses are a group of non-enveloped DNA viruses that replicate exclusively in body surface tissues, such as on the hands, the soles of the feet, on the body's mucous membranes and on the genitals. The green structure is made up of nucleocapsid proteins. Magnification: x170,000 when printed 10 centimetres wide.